According to the jock/geek paradigm, these guys are geeks because they play D&D but jocks because they shoot people in the face for a paycheck.
When teaching the game to younger players, I think it's important to concentrate on fun instead of rules minutae. That helps keep them coming back.
People read less? I am not sure that is true, especially today. If you're browsing the web, you're reading (and writing) a lot. You don't read the bible, sci-fi novels or history books, but you do read a lot in chats, message boards, blogs and even in your typical MMO (quest infos, chats).
Also, I am certain that a lot of MMOs and other video games promote not just button-klicking, but also understanding the mechanics of the game or at least figuring out which set of abilities gives you the most DPR (which typically involves math.)
I tend to believe that we overhtink too much when discussing why we play, how to play or who plays, we should focus more on just playing.
And this also applies to "young gamers" - If you want young people to play, invite them to play. Have a kid in your WoW guild that seems as if it might also be a good table-top player - invite it to a play-by-post/chat game, or a game with one of the virtual game tables. If it's in your neighborhood, invite it your regular game.
You could also slowly draw people in - start with regular card games, than some board games, and than introduce them to D&D. Avoid overwhelming the player - make a short, one session game that allows for more, but doesn't demand it.
Talk about your hobby like you would about any other hobby. If you're playing WoW, you might occasionally chat about other games you also play - why not also D&D?
Don't preemptively defend yourself against stereotypes. If people bring up stereotypes, don't dwell on it. It might be enough to point out a stereotype of whatever he usually does (be it sports, World of Warcraft, blondes, Hispanic, math, whatever).
In the end, face one thing: You won't draw in everyone. But neither does World of Warcraft, Baseball or Seinfeld.
But I am not convinced that RPGs are a dying hobby. It grants me an experience other games do not, so it will always have a place. RPGs might get a smaller share because there are so many options, but that doesn't mean they die out.
WoW is attractive because it can be played whenever a person has spare time, unlike pen-and-paper RPG's which require several people to coordinate their schedules. Never underestimate the power of a low barrier to entry.WOW has it easier because the intellectual energy required to play is much less.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.